Developers of Howard County's mixed-use projects -- modeled after Columbia's villages -- will have to study their impact on the county's finances before construction if Councilman C. Vernon Gray gets his way.

Gray, an east Columbia Democrat, said the fiscal impact studies would help county officials judge whether the developments, including the Rouse Co.'s 525-acre project proposed for North Laurel, would help or hurt the county's bottom line.

"This cost-benefit analysis will protect taxpayers," Gray said.

County Planning Director Joe Rutter and the Planning Board oppose Gray's plan, saying it is unnecessary.

But Gray's proposal underscores widespread worries that residential construction, which typically costs more in services than it generates in taxes, is racing ahead while business growth lags.

Nonresidential properties -- businesses and institutions -- make up less than 19 percent of Howard's tax base; officials have set a target of 25 percent.

That makes it harder for the county to provide schools, roads, parks and police protection without raising taxes and fees.

There is general agreement on the problem, but officials disagree on how to remedy it.

Gray's plan to require fiscal impact studies could give county officials reason to force changes in the mix of residential and business properties within mixed-use projects.

It also might give ammunition to opponents looking to stall projects, said Councilman Charles C. Feaga, a West Friendship Republican.

Feaga said the fiscal impact studies would be an unfair burden on developers and landowners.

"You might be four or five years getting the results," he said after the meeting. "You can't freeze development."

At the hearing, a Sierra Club lobbyist, Nancy Davis of Clarksville, supported Gray's proposal.

"No business would plan its business without first doing a cost-benefit analysis, and government should do the same," Davis said.

Tom Flynn, president-elect of the North Laurel Civic Association, said such fiscal studies would help county officials make wise decisions on zoning, particularly as Howard's undeveloped land dwindles.

"We have to really watch how we're developing now," Flynn said. just have less room to maneuver if we do make mistakes."

Rutter said the county should monitor the mix of residential and business growth overall, not in individual projects.

No other type of development in Howard requires fiscal impact analyses.